Compare 640 vs 643
| Property | 640 | 643 |
|---|---|---|
| Type | composite number | prime |
| Unique factors | 2 | 1 |
| Total factors | 8 | 1 |
| Prime factorization | 27 × 51 | 6431 |
| Prime factorization | 2 × 2 × 2 × 2 × 2 × 2 × 2 × 5 | 643 |
| Divisors count | 16 | 2 |
| Divisors | 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 128, 160, 320, 640 | 1, 643 |
| Number of properties | 0 | 7 |
| Additive primes | 63rd | |
| Cousin primes (1st member) | 29th | |
| Left-truncatable primes | 38th | |
| Lucky primes | 33rd | |
| Primes | 117th | |
| Prime triplets (2nd member) | 24th | |
| Twin primes (2nd member) | 29th | |
| Roman numberals | DCXL | DCXLIII |
| Base 2 | 10100000002 | 10100000112 |
| Base 3 | 2122013 | 2122113 |
| Base 4 | 220004 | 220034 |
| Base 5 | 100305 | 100335 |
| Base 6 | 25446 | 25516 |
| Base 7 | 16037 | 16067 |
| Base 8 | 12008 | 12038 |
| Base 9 | 7819 | 7849 |
| Base 10 | 64010 | 64310 |
| Base 11 | 53211 | 53511 |
| Base 12 | 45412 | 45712 |
| Base 13 | 3a313 | 3a613 |
| Base 14 | 33a14 | 33d14 |
| Base 15 | 2ca15 | 2cd15 |
| Base 16 | 28016 | 28316 |